Related Clues:
- Assembly line add-on, perhaps
- Highway toll unit
- It may have a linchpin
- Wheel connection
- What a driver takes
- Drivetrain connection
- Wheel supporter
- Move in a circle
- Unicycle part
- Revolutionary car part?
- Turner on a game show
- A semi lacks a front one
- Wagon roller
- Shaft under the floorboard
- Drivetrain component